Isobaric vapor-liquid equilibria (VLE) are experimentally measured for the binary systems of dimethyl carbonate (DMC)+ ethylene carbonate and methanol + ethylene carbonate at 101.325kPa. The thermodynamic consistency ...Isobaric vapor-liquid equilibria (VLE) are experimentally measured for the binary systems of dimethyl carbonate (DMC)+ ethylene carbonate and methanol + ethylene carbonate at 101.325kPa. The thermodynamic consistency of these experimental data is tested with an available statistic method. Interaction parameters of the carbonate group -OCOO- with the group -CH3, ACH, CH3OH and CH3COO- in UNIFAC model are determined using the experimental and literature VLE data. The results show that the calculated VLE data using the new UNIFAC parameters agree excellently with the experimental data in this work and in literature. These results are useful in the research on DMC and diphenyl carbonate synthesis by transesterification in design of reactor and distillation tower.展开更多
Stylopeptide 1 synthesized and isolated from different sources exhibits a large activity difference in inhibitory effect on the growth of a cancer cell.Based on the different amounts of methanol and water during synth...Stylopeptide 1 synthesized and isolated from different sources exhibits a large activity difference in inhibitory effect on the growth of a cancer cell.Based on the different amounts of methanol and water during synthesis,isolation and purification of the cyclic peptides,molecular dynamics(MD) was employed to simulate the conformation of stylopeptide 1 in methanol and aqueous environments.The comparative results show that the backbone ring was more rigid in methanol than in water.In methanol,two β-turns and three hydrogen bonds were well conserved throughout the simulation,whereas no hydrogen bonds or turns were preserved in water.The activity difference of stylopeptide 1 seemed to be attributed to the solvent effect on its conformation.展开更多
Indium oxide(In_2O_3) has demonstrated to be an effective non-noble metal catalyst for methanol steam reforming reaction(MSR).However, the reaction mechanism of MSR and crucial structure-activity relations determining...Indium oxide(In_2O_3) has demonstrated to be an effective non-noble metal catalyst for methanol steam reforming reaction(MSR).However, the reaction mechanism of MSR and crucial structure-activity relations determining the catalytic performance of In_2O_3 are still not fully understood yet. Using density functional theory(DFT) calculation, we systematically investigate the MSR process over a high-index In_2O_3(211) and a favoured catalytic cycle of MSR is determined. The results show that In_2O_3(211) possesses excellent dehydrogenation and oxidizing ability, on which CH_3 OH can readily adsorb on the In4 c site and be easily activated by the reactive lattice oxygens, resulting in a total oxidation into CO_2 rather than CO, while the H_2 formation through surface H–H coupling limits the overall MSR activity because of the strong H adsorption on the two-coordinated lattice O(O_(2c)). Our analyses show that the relatively inert three-coordinated lattice O(O_(3c)) could play an important catalytic role. To uncover the influence of the local coordination of surface In atoms and lattice O on the catalytic activity, we evaluate the activity trend of several types of In_2O_3 surfaces including(211),(111), and(100) by examining the rate-limiting, which reveals the following activity order:(211)>(111)>(100). These findings provide an in-depth understanding on the MSR reaction mechanism over In_2O_3 catalysts and some basic structure-activity relations at the atomic scale, could facilitate the rational design of In_2O_3-based catalysts for MSR by controlling the local coordination environment of surface active sites.展开更多
文摘Isobaric vapor-liquid equilibria (VLE) are experimentally measured for the binary systems of dimethyl carbonate (DMC)+ ethylene carbonate and methanol + ethylene carbonate at 101.325kPa. The thermodynamic consistency of these experimental data is tested with an available statistic method. Interaction parameters of the carbonate group -OCOO- with the group -CH3, ACH, CH3OH and CH3COO- in UNIFAC model are determined using the experimental and literature VLE data. The results show that the calculated VLE data using the new UNIFAC parameters agree excellently with the experimental data in this work and in literature. These results are useful in the research on DMC and diphenyl carbonate synthesis by transesterification in design of reactor and distillation tower.
基金Supported by Teaching and Research Award Program for Outstanding Young Teachers in High Education Institutions of Ministry of Education,China(No.NCET-05-0279)Liaoning Science and Technology Foundation,China(No.2005226008)
文摘Stylopeptide 1 synthesized and isolated from different sources exhibits a large activity difference in inhibitory effect on the growth of a cancer cell.Based on the different amounts of methanol and water during synthesis,isolation and purification of the cyclic peptides,molecular dynamics(MD) was employed to simulate the conformation of stylopeptide 1 in methanol and aqueous environments.The comparative results show that the backbone ring was more rigid in methanol than in water.In methanol,two β-turns and three hydrogen bonds were well conserved throughout the simulation,whereas no hydrogen bonds or turns were preserved in water.The activity difference of stylopeptide 1 seemed to be attributed to the solvent effect on its conformation.
基金supported by the National Natural Science Foundation of China(21333003,21622305)Young Elite Scientist Sponsorship Program by China Association for Science and Technology(YESS20150131)+1 种基金"Shu Guang"project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(13SG30)the Fundamental Research Funds for the Central Universities(WJ616007)
文摘Indium oxide(In_2O_3) has demonstrated to be an effective non-noble metal catalyst for methanol steam reforming reaction(MSR).However, the reaction mechanism of MSR and crucial structure-activity relations determining the catalytic performance of In_2O_3 are still not fully understood yet. Using density functional theory(DFT) calculation, we systematically investigate the MSR process over a high-index In_2O_3(211) and a favoured catalytic cycle of MSR is determined. The results show that In_2O_3(211) possesses excellent dehydrogenation and oxidizing ability, on which CH_3 OH can readily adsorb on the In4 c site and be easily activated by the reactive lattice oxygens, resulting in a total oxidation into CO_2 rather than CO, while the H_2 formation through surface H–H coupling limits the overall MSR activity because of the strong H adsorption on the two-coordinated lattice O(O_(2c)). Our analyses show that the relatively inert three-coordinated lattice O(O_(3c)) could play an important catalytic role. To uncover the influence of the local coordination of surface In atoms and lattice O on the catalytic activity, we evaluate the activity trend of several types of In_2O_3 surfaces including(211),(111), and(100) by examining the rate-limiting, which reveals the following activity order:(211)>(111)>(100). These findings provide an in-depth understanding on the MSR reaction mechanism over In_2O_3 catalysts and some basic structure-activity relations at the atomic scale, could facilitate the rational design of In_2O_3-based catalysts for MSR by controlling the local coordination environment of surface active sites.
